US20090283038A1 - Film forming method and apparatus - Google Patents

Abstract

A film forming method, for depositing a thin film on a surface of a substrate mounted on a mounting table disposed in a vacuum processing chamber, includes an adsorption process for adsorbing a film forming material on the substrate by introducing a source gas into the processing chamber; and a reaction process for carrying out a film forming reaction, after the adsorption process, by introducing an energy transfer gas into the processing chamber and supplying thermal energy to the film forming material adsorbed on the substrate. By repeating the above process, the thin film is formed on the substrate in a layer-by-layer manner.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation application of pending U.S. application Ser. No. 11/608,504, filed on Dec. 8, 2006, which claims priority to Japan Patent Application No. 2005-335152, filed on Dec. 8, 2005. The entire contents of each of the above applications are incorporated herein by reference.
FIELD OF THE INVENTION
• The present invention relates to a film forming method and apparatus; and, more particularly, to a film forming method for forming a desired thin film on a surface of a substrate by using an ALD (atomic layer deposition) method and a film forming apparatus therefor.
BACKGROUND OF THE INVENTION
• As for a representative film forming method for forming a solid thin film on a surface of a substrate such as a semiconductor wafer or the like, there is known a CVD (chemical vapor deposition) method. When a film is formed by using the CVD method, a source needs to be activated by applying energy to a source gas. Accordingly, there has been employed a CVD method for supplying thermal energy to a source gas through a substrate heated by a heater provided at a mounting table for mounting thereon the substrate or a plasma CVD method for supplying energy of a plasma generated in a space above a substrate by introducing a source gas into the atmosphere thereof.
• A film forming apparatus for manufacturing an advanced very large scale integrated circuit needs to have a performance (a step coverage performance) of forming a high-quality thin film of a uniform thickness along surfaces of holes/grooves previously formed on a surface of a semiconductor wafer with a diameter/width of tens of nanometers.
• In order to obtain a high step coverage performance, a surface reaction needs to take place by activating a source gas on an uppermost surface of a substrate, not by activating it in a gas phase space above the substrate. However, in the CVD method for forming a film by continuously supplying a source gas, a reactant gas and energy, certain source gases may cause a gas phase reaction by an excessive activation thereof in a gas phase. Since the gas phase reaction greatly deteriorates the step coverage performance, there arises a need to suppress the gas phase reaction and facilitate the surface reaction in order to maintain the high step coverage performance.
• As for another method for forming a thin film on a surface of a substrate, there is known an atomic layer deposition (ALD) method. With the ALD method, a thin film having high step coverage can be formed on a substrate disposed inside a vacuum chamber by repetitively performing a film forming process and a purge process. In the ALD film forming process, a reaction is carried out by supplying energy to a monomolecular or a multimolecular adsorption layer adsorbed on a surface, the adsorption layer being formed of molecules of a source compound. In the purge process, the atmosphere inside the vacuum chamber is substituted.
• The ALD method for forming a film while suppressing a gas phase reaction was suggested in 1977 by Suntola et al. (see U.S. Pat. No. 4,058,430). The method is performed by alternately supplying a source gas and a reactant gas to a substrate at different timings, as shown inFIG. 24, and then removing a residual source gas and a by-product gas of a previous cycle remaining in a gas phase with a non-reactive purge gas before supplying the source gas and the reactant gas again. The gas phase reaction can be suppressed by repeating those cycles. Further, the high step coverage performance can be maintained by restricting the reaction to take place at the uppermost surface of the substrate. There are plenty of reports on the ALD method (see, e.g., R. L. Puurunen, “Surface chemistry of atomic layer deposition: A case study for the triethylaluminum/waterprocess”, Journal of Applied Physics, APPLIED PHYSICS REVIEW, vol. 97, p 121301 (2005)).
• In an initial ALD method, although the source gas and the reactant gas are separately provided as shown inFIG. 24, the energy (heat) is constantly supplied. This is because the initial ALD method supplies the thermal energy to a surface of a substrate via the substrate by heating the entire substrate as in the thermal CVD method and, therefore, a time responsiveness in controlling an on/off of energy supply becomes poor (see, e.g., U.S. Pat. No. 4,389,973). Such an ALD method is referred to as “thermal ALD method”. In this method, since the energy is constantly supplied during a source gas supply process, parts of the source gas may ever cause an self-pyrolysis reaction in a gas phase by receiving the thermal energy transferred in the gas phase from the substrate, which leads to a deterioration of the step coverage performance.
• Moreover, since the entire substrate is heated constantly during the processing, a solid layer that has been formed by a previous process may be deteriorated by the heat.
• To solve those drawbacks, Sherman et al. has suggested an ALD method for supplying energy by radicals generated by an RF power supply (see U.S. Pat. No. 5,916,365). Further, Chiang et al. has suggested a method for supplying energy by radicals and ions generated from a plasma (see U.S. Pat. No. 6,416,822). In these methods, the energy is supplied not by heat but by chemically active species (radicals, ions or combination thereof) generated from the RF power supply, so that an ON/OFF of energy supply can be controlled with fine time-responsiveness. Such an ALD method is referred to as “a plasma-assisted ALD method”.
• In the plasma-assisted ALD method, a source gas supplying process and an energy supplying process can be carried out at different timings. Therefore, it is possible to prevent a self-pyrolysis reaction of the source gas from taking place during the source gas supplying process, the self-pyrolysis reaction being caused by the continuous supply of thermal energy. Further, since such a method is not a method for supplying energy through a substrate being continuously heated, it is possible to avoid the problem of deteriorating the previously formed solid layer with the heat.
• However, the method using as an energy source radicals or ions generated from a plasma has new problems to be described as follows.
• Firstly, the excessively high energy of the active species (radicals, ions and electrons) generated from a plasma inflicts a serious physical damage or causes a chemical deterioration on a base layer of a substrate where a film will be formed (see, e.g., A. Grill et al, “Hydrogen plasma effects on ultra low-k porous SiCOH dielectric”, Journal of Applied Physics, vol. 98, p 074502 (2005)).
• Secondly, the active species also collide against not only the substrate but also an inner surface of an apparatus in contact with the plasma, thereby causing a physical sputtering, which in turn result in impurity incorporation into the surface of the substrate.
• Thirdly, since the energy is also supplied by the active species to side chain groups contained in the source gas that are desirably to be removed by the reaction, the side chain groups may be incorporated as undesired impurities into the film.
• Fourthly, a potential gradient generated inside the apparatus electrically may destroy fine integrated circuits formed on the substrate.
• Fifthly, high energy ultraviolet rays generated from the plasma may deteriorate the base layer of the substrate.
• As long as the energy is supplied by using the plasma, the aforementioned problems may be only partially, but not completely, avoided.
• In order to avoid those problems generated in supplying energy by the plasma, Chiang et al. has suggested a method for supplying energy by light (see, U.S. Pat. No. 6,878,402). In case the energy is supplied by irradiating light on a surface of a substrate, a window for transmitting the light needs to be provided above the substrate. Since, however, a surface of the window becomes dirty during a film forming process, the light is reflected or absorbed and, thus, an intensity of the light reaching the substrate decreases. Moreover, in case the surface of a processing target substrate is made of a metal, the light is reflected on the surface of the substrate, which hinders the energy supply for the reaction.
SUMMARY OF THE INVENTION
• It is, therefore, an object of the present invention to provide a film forming method capable of forming a high-quality thin film having high step coverage on a surface of a substrate without deteriorating a thin film previously formed on the substrate with heat or inflicting plasma damages thereon.
• The present inventors have achieved the present invention by conceiving an energy supply method based on the ALD method and finding solutions to the aforementioned problems.
• In accordance with a first aspect of the present invention, there is provided a film forming method for depositing thin films on a surface of a substrate mounted on a mounting table arranged in a vacuum evacuable processing chamber, the method comprising the steps of: an adsorption process for adsorbing a film forming material on the substrate by introducing a source gas into the processing chamber; and a reaction process for carrying out a film forming reaction, after the adsorption process, by introducing an energy transfer gas into the processing chamber and supplying thermal energy to the film forming material adsorbed on the substrate.
• In view of the first aspect, it is preferable to further include a purge process for introducing a purge gas into the processing chamber. Preferably, the adsorption process and the reaction process are alternately performed, and the purge process is performed therebetween. Moreover, it is preferable to further include a pressure increasing process for increasing a pressure inside the processing chamber before the reaction process. In such a case, it is preferable that a pressure decreasing process for decreasing an inner pressure of the processing chamber is provided upon or after the reaction process is completed. In the reaction process, it is preferable to introduce a reactant gas chemically participating in the film forming reaction in addition to the energy transfer gas. Further, it is preferable that the reactant gas is one of a reduction gas, a carbonization gas, a nitrification gas and an oxidizing gas.
• Further, it is preferable that the energy transfer gas is selected among a reduction gas, a carbonization gas, a nitrification gas and an oxidizing gas.
• Preferably, the source gas is introduced and exhausted such that a gas flow is formed in a direction parallel to the surface of the substrate mounted on the mounting table. Furthermore, preferably, the source gas is introduced and exhausted such that a gas flow is formed in a direction of colliding against the surface of the substrate mounted on the mounting table. Preferably, the energy transfer gas is injected toward the surface of the substrate mounted on the mounting table, the surface having the film forming material adsorbed thereon.
• Preferably, the adsorption process is performed while controlling a temperature of the substrate mounted on the mounting table to a level at which the film forming material is absorbable.
• Preferably, the film forming material contains at least one metal element selected from a group consisting of Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Zr, Mo, Ru, Rh, Pd, Ag, Ba, Hf, Ta, W, Re, Ir and Pt. Further, it is preferable that the thin films are deposited on the substrate by repeating a plurality of cycles of performing a film forming reaction with a film forming material of a monomolecular or a multimolecular adsorption layer through an atomic layer deposition method.
• In accordance with a second aspect of the present invention, there is provided a computer-executable program for controlling the processing chamber such that the film forming method of the first aspect of the present invention is performed.
• In accordance with a third aspect of the present invention, there is provided a computer readable storage medium for storing therein a computer-executable program, wherein the control program controls the processing chamber such that the film forming method of the first aspect of the present invention is performed.
• In accordance with a fourth aspect of the present invention, there is provided a film forming apparatus including: a processing chamber accommodating therein a substrate, for performing a film forming process; a mounting table for mounting thereon the substrate in the processing chamber; a source gas inlet for introducing a source gas into the processing chamber; an energy transfer gas inlet for injecting an energy transfer gas toward a surface of the substrate mounted on the mounting table in the processing chamber; a gas exhaust unit for vacuum exhausting an inside of the processing chamber; and a controller for controlling the film forming method described in any one ofclaims1 to14 to be performed.
• In accordance with a fifth aspect of the present invention, there is provided a film forming apparatus including: a processing chamber accommodating therein a substrate, for performing a film forming process; a mounting table for mounting thereon the substrate in the processing chamber; a source gas inlet for introducing a source gas into the processing chamber; an energy transfer gas inlet for injecting an energy transfer gas toward a surface of the substrate mounted on the mounting table in the processing chamber; and a gas discharge port connected with a gas exhaust unit for vacuum exhausting an inside of the processing chamber, wherein the source gas inlet and the gas discharge port are provided such that the introduced source gas flows in a direction parallel to a surface of the substrate mounted on the mounting table before being exhausted.
• In accordance with a sixth aspect of the present invention, there is provided a film forming apparatus including: a processing chamber accommodating therein a substrate, for performing a film forming process; a mounting table for mounting thereon the substrate in the processing chamber; a source gas inlet for introducing a source gas into the processing chamber; an energy transfer gas inlet for injecting an energy transfer gas toward a surface of the substrate mounted on the mounting table in the processing chamber; and a gas discharge port connected with a gas exhaust unit for vacuum exhausting an inside of the processing chamber by a depressurization, wherein the source gas inlet and the gas discharge port are provided such that the source gas is introduced and exhausted in a direction of colliding against the surface of the substrate mounted on the mounting table.
• In accordance with the film forming apparatus of the fifth and the sixth aspect of the present invention, it is preferable that the mounting table includes a temperature control unit for controlling a temperature of the substrate mounted thereon to a level at which a source material is absorbable on the substrate.
• In accordance with the film forming method of the present invention, the adsorption process for adsorbing a film forming material on a substrate by introducing a source gas into a processing chamber is performed at a different timing from the reaction process for carrying out a film forming reaction by introducing an energy transfer gas into the processing chamber and supplying thermal energy to the film forming material adsorbed on the substrate. Accordingly, the whole substrate does not need to be heated for a long period of time. Further, since the thermal energy is supplied by using the energy transfer gas, a surface of the substrate is mainly heated. Therefore, it is possible to avoid drawbacks of a conventional thermal ALD method, such as a deterioration of a solid layer due to a heat, a deterioration of step coverage due to a self-pyrolysis of a gaseous source gas and the like. Moreover, it is also possible to avoid drawbacks of a plasma-assisted ALD method, such as a damage inflicted on a substrate due to a plasma, a deterioration of a film quality due to a sputtering or an excessive activation of a source gas, and the like. Furthermore, the present invention provides a high energy efficiency of the entire process.
• Moreover, in accordance with the film forming apparatus of the present invention, a stage heater for maintaining a high temperature of a substrate, a plasma generating device and the like are not required and, also, a high-quality thin film can be formed with a simple configuration.
• While the invention has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
• The above and other objects and features of the present invention will become apparent from the following description of embodiments, given in conjunction with the accompanying drawings, in which:
• FIG. 1 is a cross sectional view showing a schematic configuration of a film forming apparatus in accordance with a first embodiment of the present invention;
• FIGS. 2A and 2B describe arrangements of gas injection openings formed on a bottom surface of a shower head, whereinFIG. 2A provides an example of a concentric arrangement, andFIG. 2B depicts an example of a grid pattern arrangement;
• FIG. 3 illustrates a schematic configuration of a heater provided around the injection openings;
• FIG. 4 presents a flowchart for explaining exemplary processes of a film forming method of the present invention;
• FIG. 5 represents a flowchart for explaining another exemplary processes of the film forming method of the present invention;
• FIG. 6 depicts a timing chart of the exemplary processes ofFIG. 5;
• FIG. 7 provides a flowchart for explaining still another exemplary processes of the film forming method of the present invention;
• FIG. 8 describes a timing chart of the exemplary processes ofFIG. 7;
• FIG. 9 is a flowchart for explaining still another exemplary processes of the film forming method of the present invention;
• FIG. 10 shows a timing chart of the exemplary processes ofFIG. 9;
• FIGS. 11A to 11J illustrate schematic views for explaining a principle of the film forming method of the present invention;
• FIG. 12 presents a schematic configuration of a film forming apparatus in accordance with a second embodiment of the present invention;
• FIG. 13 represents a schematic configuration of a film forming apparatus in accordance with a third embodiment of the present invention;
• FIG. 14 describes a timing chart of a film formation of a first example;
• FIG. 15 illustrates a timing chart of a film formation of a second example;
• FIG. 16 provides a timing chart of a film formation of a third example;
• FIG. 17 shows a timing chart of a film formation of a fifth example;
• FIG. 18 offers a timing chart of a film formation of a sixth example;
• FIG. 19 depicts a timing chart of a film formation of a seventh example;
• FIG. 20 presents a timing chart of a film formation of a ninth example;
• FIG. 21 represents a timing chart of a film formation of a tenth example;
• FIG. 22 illustrates a schematic configuration of a shower head having a cylindrical heater;
• FIG. 23 shows a schematic configuration of the cylindrical heater; and
• FIG. 24 offers a timing chart of a conventional thermal ALD.
DETAILED DESCRIPTION OF THE EMBODIMENT
• Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
• FIG. 1 is a cross sectional view schematically showing an exemplary film forming apparatus suitable for performing a film forming method of the present invention. Such afilm forming apparatus100 has a substantially cylindricalairtight chamber1. Acircular opening2 is formed at a central portion of a bottom wall1aof thechamber1. Further, arranged inside thechamber1 is a mounting table3 made of ceramic such as AlN or the like, for horizontally supporting a wafer W (a semiconductor substrate). An insulatingunit4 is provided between the mounting table3 and the bottom wall1aand airtightly contacted with the bottom wall1aof thechamber1.
• Agas exhaust port5 is formed on asidewall1bof thechamber1 and connected with agas exhaust unit7 via agas exhaust line6 connected therewith, thegas exhaust unit7 having a high speed vacuum pump. Moreover, a conductancevariable valve6ais provided in thegas exhaust line6 to control a gas exhaust amount from thechamber1. As for the conductancevariable valve6a, there can be used, e.g., a butterfly valve or the like. By operating thegas exhaust unit7, a gas inside thechamber1 is exhausted and, further, an inside of thechamber1 can be depressurized to a predetermined vacuum level at a high speed via thegas exhaust line6.
• Ashower head10 is provided on aceiling wall1cof thechamber1. Disposed on an upper wall of theshower head10 is agas inlet port12 for introducing a gas into theshower head10. Connected to thegas inlet port12 is aline13 for supplying an energy transfer gas such as He, Ar, Kr, Xe, H₂, N₂, CO₂, CH₄or the like. The other end portion of theline13 connected with thegas inlet port12 is branched into two. One is connected with an energy transfergas supply source23avia amass flow controller21aandvalves22aprovided in its forward and backward direction, and the other is connected with a reactantgas supply source23bvia amass flow controller21bandvalves22bprovided in its forward and backward direction.
• Adiffusion space14 is formed inside theshower head10. The gas introduced from thegas inlet port12 is diffused in thediffusion space14. Formed at a lower portion of theshower head10 are a plurality ofgas injection openings11 for discharging the energy transfer gas and the reactant gas toward the mounting table3. Thegas injection openings11 may be arranged in any pattern. For example, they can be formed in a concentric pattern as shown inFIG. 2A or in a grid pattern as illustrated in FIG.2B. Further, a diameter or the number of thegas injection openings11 can be appropriately determined depending on film types.
• Provided near each of thegas injection openings11 of theshower head10 is aheater15 serving as heating units for heating the energy transfer gas inside theshower head10. Moreover, insulatingunits16 are provided around theheaters15 to insulate theheaters15, the insulatingunits16 being made of a material having a low thermal conductivity, such as heat resistant synthetic resin, quartz, ceramic or the like.FIG. 3 shows an exemplary configuration of aheater15. Theheater15 includes a cylindricalceramic member15aformed to surround thegas injection openings11 and a resistance (heating wire)201 embedded in a coil shape in theceramic member15a. By supplying power from a heater power supply (not shown) to theresistance201 via alead line202, the energy transfer gas flowing through inside the resistance (heating wire)201 can be instantly and effectively heated.
• Agas inlet port17 is provided at the opposite side of thegas exhaust ports5 provided on thesidewall1bof thechamber1 and connected with agas exhaust line18 for supplying a source gas and a purge gas to thechamber1. The other end portion of theline18 is branched into two. One is connected with connected with a sourcegas supply source26 via amass flow controller24aandvalves25aprovided in its forward and backward direction, and the other is connected with a purgegas supply source27 via amass flow controller24bandvalves25bprovided in its forward and backward direction.
• A film forming sourcegas supply source26 is configured to supply a source gas. The source gas contains a metal element in a part of a molecular structure and supplies the metal element as a main constituent of a thin film produced by a reaction. As for the metal element, there can be employed a third periodic element in the periodic table, such as Al, Si or the like, fourth periodic element such as Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge or the like, fifth periodic element such as Zr, Mo, Ru, Rh, Pd, Ag or the like or sixth periodic element such as Ba, Hf, Ta, W, Re, Ir, Pt and the like.
• As for a metal compound forming a source gas, there can be used one of the following exemplary metal compounds:
• • Al: Al(CH₃)₃
  • Ti: Ti[N(CH₃)₂]₄; tetrakis(dimethylamino)titanium (TDMAT)
  • Cr: Cr(CO)₆
  • Mn: Mn₂(CO)₁₀
  • Fe: Fe(CO)₅, Fe₂(CO)₉, Fe₃(CO)₁₂
  • Co: Co₂(CO)₈
  • Ni: Ni(CO)₄, Ni(acac)₂; acac representing Acetylacetone (2,4-pentadion)
  • Cu: (Hfac)CuTMVS; Hfac representing hexafluoroacetylacetone, and TMVS representing trimethylvinylsilane
  • Zn: Zn(CH₃)₂
  • Ge: Ge(OCH₃)₄
  • Zr: Zr(O-t-C₄H₉)₄
  • Mo: Mo(CO)₆
  • Ru: Ru₃(CO)₁₂, Ru(EtCp)₂; EtCp representing ethyl cyclopantadiene
  • Rh: Rh₄(CO)₁₂
  • Pd: Pd(OAc)₂; OAc representing acetate
  • Ag: Ag[O₂C—C(CH₃)₃]; 2,2-dimethylpropionate silver (I)
  • Ba: Ba(O₂C₁₁H₁₉)₂; Bis(dipivaloymethanato)barium
  • Hf: Hf (C₁₁H₁₉O₂)4
  • Ta: Ta(N-t-C₅H₁₁) [N(CH₃)₂]₃; Tertiaryamylimidotris (dimethylamido) tantalum
  • W: W(CO)₆
  • Re: Re₂(CO)₁₀
  • Ir: Ir(C₅H₄C₂H₅) (C₈H₁₂); ethylcyclopentadienyl(1,5-cyclooctadiene)iridium
  • Pt: Pt(C₅H₄C₂H₅) (CH₃)₃; ethylcyclopentadienyl(trimethyl)platinum
• If necessary, the film forming sourcegas supply source26 may be provided with a plurality of source gas supply sources (not shown). Further, in order to introduce the source gas into the chamber, there may be provided, e.g., a heating equipment for sublimating a solid film forming material, a vaporizer for vaporizing a liquid film forming material and the like in addition to a carrier gas supply source for supplying a carrier gas such as Ar or the like (all not shown).
• The purgegas supply source27 is configured to supply a purge gas. The purge gas is used to purge a source gas remaining in a gas phase, by-products generated in the gas phase by a reaction and an energy transfer gas containing a large amount of thermal energy. As for the purge gas, there can be employed H₂gas or a non-reactive gas such as Ar gas, He gas, N₂gas or the like. By introducing the purge gas, the residual source gas in theline18 can be exhausted. Further, the by-products can be removed by substituting the atmosphere inside thechamber1. Furthermore, the wafer W can be cooled.
• Aclamp ring28 for fixing the wafer W is provided at an outer peripheral portion of the mounting table3. Theclamp ring28 moves up and down by an elevatingmechanism29 and fixedly presses downward the wafer W mounted on the mounting table3. Although a thickness of theclamp ring28 is exaggerated inFIG. 1, the actual thickness is set such that a contact between the source gas and a surface of the wafer W is not interfered. Further, the mounting table3 is provided with three wafer supporting pins (not shown) capable of protruding and retracting relative to a surface of the mounting table3 so that the wafer W can be supportively lifted up and down.
• A temperature controlmedium chamber30 is formed inside the mounting table3 and configured to control a temperature of the mounting table3 by introducing thereinto a temperature control medium of a predetermined temperature, e.g., water or Galden (trademark) as a fluorine-based non-reactive liquid, through anintroduction path31aand then discharging it through adischarge path31b.
• Agas channel32 is formed inside the mounting table3 from a lower portion of the mounting table3 to a top surface of the mounting table3, i.e., a mounting surface of the wafer W. Also, thegas channel32 is branched into a plurality ofgas injection openings32anear the mounting surface to thereby supply a heat transfer gas, e.g., He gas or the like, to a backside of the wafer W in multiple places at a predetermined pressure. In this way, the temperature of the mounting table3 is transferred to the wafer W and, accordingly, the temperature thereof is controlled.
• The temperature controlmedium chamber30 for circulating the temperature control medium and thegas channel32 for supplying the heat transfer gas to the backside of the wafer W cooperatively serve as a temperature control unit for controlling a temperature of the wafer W.
• Provided on thesidewall1bof thechamber1 are a loading/unloading port (not shown) for loading/unloading the wafer W to/from a transfer chamber (not shown) disposed adjacent to thefilm forming apparatus100 and a gate valve (not shown) for opening/closing the loading/unloading port.
• Each component of thefilm forming apparatus100 is connected with aprocess controller50 having a CPU and controlled by theprocess controller50. Theprocess controller50 is connected with auser interface51 having a keyboard, a display and the like. A process operator uses the keyboard when inputting commands for managing theplasma processing apparatus100, and the display is used to display the operation status of thefilm forming apparatus100.
• Also, theprocess controller50 is connected with astorage unit52 for storing therein recipes including control programs (software) for implementing various processes in thefilm forming apparatus100 under the control of theprocess controller50, processing condition data and the like.
• If necessary, theprocess controller50 executes a recipe read from thestorage unit52 in response to instructions from theuser interface51, thereby implementing a desired process in thefilm forming apparatus100 under the control of theprocess controller50. For example, theprocess controller50 controls each mass flow controller, each valve and thegas exhaust unit7. Accordingly, the source gas, the carrier gas, the purge gas and the like are controlled to be supplied at required flow rates thereof, or the supply thereof is stopped. Furthermore, the recipes such as the control programs, the processing condition data and the like can be read from a computer-readable storage medium, e.g., a CD-ROM, a hard disk, a flexible disk, a flash memory or the like, or transmitted on-line from another device via, e.g., a dedicated line when necessary.
• Hereinafter, a sequence of forming a desired film by using thefilm forming apparatus100 will be described with reference toFIG. 4. First of all, while a gate valve (not shown) is opened, the wafer W is loaded into thechamber1 via the loading/unloading port and then mounted on the mounting table3 (step S11). Next, a temperature control medium of a predetermined temperature is introduced into the temperature controlmedium chamber30 and, also, a heat transfer gas such as He gas or the like is introduced into thegas channel32. By injecting the heat transfer medium gas from themultiple injection openings32ato the backside of the wafer W, a temperature of the wafer W is controlled until it reaches a level enabling the film forming material to be easily adsorbed on a surface of the wafer W (step S12). Although the temperature can vary depending on types of film forming material, it can be controlled between −20° C. and 100° C., for example.
• The inside of thechamber1 is exhausted by a vacuum pump of thegas exhaust unit7. Next, while thevalves25aare opened, a source gas is supplied from the film forming sourcegas supply source26 to thechamber1 via thegas inlet port17 at a flow rate controlled by themass flow controller24a. By performing the exhaust with an operation of thegas exhaust unit7, the source gas flows from thegas inlet port17 toward thegas exhaust port5 in a direction parallel to the surface of the wafer W mounted on the mounting table3, as indicated by white arrows ofFIG. 1. Due to the flow of the source gas, the film forming material is physically or chemically adsorbed on the surface of the wafer W (step S13). Although an inner pressure of thechamber1 during the adsorption process can vary depending on types of source materials, it is preferably controlled between 10 Pa and 1000 Pa, for example.
• Thereafter, while thevalves25aare closed and thevalves25bare opened, the purge gas is supplied from the purgegas supply source27 to thechamber1 via thegas inlet port17 at a flow rate controlled by themass flow controller24b. By performing the exhaust with an operation of thegas exhaust unit7, the atmosphere inside thechamber1 is substituted by the purge gas. Consequently, a residual gaseous source gas is removed (step S14).
• Before an energy transfer gas is introduced into the chamber, an inner pressure of thechamber1 is increased in a step S15. By increasing the pressure, when the energy transfer gas is introduced into the chamber in anext step16, a temperature can be prevented from decreasing due to an expansion of the energy transfer gas and it is possible to suppress a desorption and a diffusion of the source gas adsorbed on the surface of the wafer W.
• The pressure can be increased, under the control of theprocess controller50, by constantly introducing the purge gas and adjusting an exhaust conductance with the use of the conductancevariable valve6aarranged on thegas exhaust line6 between thegas exhaust port5 and thegas exhaust unit7. At this time, thegas exhaust unit7 and the conductancevariable valve6acooperatively serve as a pressure control unit. In the step S15 of increasing the pressure, it is preferable that the inner pressure of thechamber1 is set to be between 500 Pa and 5000 Pa, for example.
• It is preferable to carry out, after purging a certain amount of source gas by the purging step S14, the step S15 of increasing the inner pressure of thechamber1 by using the purge gas and adjusting an exhaust amount through the use of the pressure control unit. However, the steps S14 and S15 can be simultaneously performed to reduce a processing time. In other words, upon the purge gas is introduced into thechamber1, the pressure can be increased by controlling the exhaust amount with the use of pressure control unit.
• Next, while thevalves25bare closed and thevalves22aare opened, the energy transfer gas is introduced from the energy transfergas supply source23ainto thediffusion space14 of theshower head10 via thegas inlet port12 at a flow rate controlled by themass flow controller21a. The energy transfer gas facilitates a film forming reaction by conveying thermal energy transferred thereto from the heating unit such as theheaters15 or the like to the source gas adsorbed on the surface of the wafer W (substrate).
• As indicated by black arrows ofFIG. 1, the energy transfer gas introduced into thediffusion space14 is substantially vertically injected to the surface of the wafer W through the multiplegas injection openings11 disposed opposite to the wafer W in the lower portion of theshower head10. At this time, the energy transfer gas is heated to a predetermined high temperature by theheaters15 serving as the heating unit and thus collides against the surface of the wafer W with the sufficient thermal energy.
• When starting introducing the energy transfer gas into thediffusion area14 of theshower head10, it is preferable to increase an input power to theheaters15 rapidly so that the heat can be effectively conveyed to the energy transfer gas. Each of theheaters15 is controlled by theprocess controller50.
• Although a heating temperature of the energy transfer gas may vary depending on target film types, it is preferably within the range from 300 to 1000° C., for example. Further, it is preferable to maintain the inner pressure of the chamber at the level obtained in the pressure increasing process (step S15) in view of effectively performing the film forming reaction.
• Since the film forming material in the source gas is adsorbed on the surface of the wafer W as described above, the thermal energy required for the film forming reaction can be effectively supplied by injecting the high-temperature energy transfer gas thereto. Consequently, the film forming reaction is carried out on the surface of the wafer W, thereby forming a thin film corresponding to a monomolecular or a multimolecular adsorption layer of a source gas adsorbed on the surface of the wafer W (step S16). Moreover, the energy transfer gas can be heated in advance to a predetermined temperature by an external heating unit before being introduced into theshower head10. At this time, theheaters15 provided at the lower portion of theshower head10 can serve as auxiliary heating units for final temperature regulation of the energy transfer gas.
• When two or more types of gases are used as source gas to supply plural sepecies of metal elements, each of the gases may undergo the adsorption process of the step S13 and the purge process of the step S14. In addition to the energy transfer gas, a reactant gas chemically participating in the film forming reaction may be introduced in the reaction process of the step S16. That is, by opening thevalves22b, the reactant gas is introduced from the reactantgas supply source23binto thediffusion space14 of theshower head10 at a flow rate controlled by themass flow controller21band then injected into thechamber1.
• The reactant gas contains no metal elements in its molecular structure and is used to oxidize, reduce, carbonize and nitrify metal elements of a film forming material by reacting with the film forming material. As for the reactant gas, there can be used, e.g., an oxidizing gas (O₂, O₃, H₂O or the like), a reduction gas (H₂, organic acid such as HCOOH, CH₃COOH or the like, or alcohol such as CH₃OH, C₂H₅OH or the like), a carbonization gas (CH₄, C₂H₆, C₂H₄, C₂H₂or the like), a nitrification gas (NH₃, NH₂NH₂, N₂or the like) or the like. The “reactant gas” of the present invention includes the aforementioned H₂O, organic acid, alcohol, NH₂NH₂or the like, which is a liquid in a normal temperature and pressure condition. The elements forming the reactant gas may be incorporated into the film as a result of the reaction or may serve only to facilitate the reaction without being incorporated into the film. Whether to employ the reactant gas or not is determined depending on types of film forming materials and those of target films.
• Further, by heating the reactant gas, the reactant gas can be used as the energy transfer gas.
• After the reaction process of the step S16 is completed, it is preferable to stop the introduction of the energy transfer gas by closing thevalves22aand perform a pressure decreasing process for decreasing the inner pressure of the chamber1 (step S17). By reducing the inner pressure of thechamber1 after the reaction process, the energy transfer gas is exhausted and the energy supply to the surface of the wafer W is stopped in a short period of time. Further, by removing the heat from the surface of the wafer W, it is possible to prepare for a next source gas adsorption process and facilitate a desorption of by-products from the surface of the wafer W. Also, a gas purge process can be shortened by facilitating a discharge of gaseous by-products after the reaction.
• The pressure reduction is performed, under the control of theprocess controller50, for example, by exhausting the inside of thechamber1 with the use of thegas exhaust unit7, while fully opening the conductancevariable valve6aarranged on thegas exhaust line6 between thegas exhaust port5 and thegas exhaust unit7. Herein, it is preferable to decrease the pressure as much as the increase in the pressure increasing process of the step S15. In this way, the pressure can be controlled to a level required in supplying the source gas for a next cycle.
• Next, while thevalves25bare opened, the purge gas is supplied again from the purgegas supply source27 into thechamber1 via thegas inlet port17 at a flow rate controlled by themass flow controller24b. Then, the atmosphere inside thechamber1 is substituted by a low temperature purge gas by exhausting the inside of thechamber1 with thegas exhaust unit7. Accordingly, the thermal energy conveyed by the energy transfer gas is removed and, also, reaction by-products existing in the gas phase or absorbed on the surface of the wafer W are removed (step S18). In other words, the heat is removed from the surface of the wafer W by purging the energy transfer gas in the purge process of the step S18. As a result, it is possible to prepare for a source gas adsorption process of a next cycle. Further, a concentration of impurities in the film can be decreased by purging the gaseous reaction by-products.
• In thefilm forming apparatus100, a high-quality thin film corresponding to a monomolecular or a multimolecular adsorption layer of a film forming material can be formed on the wafer W by performing main processes including the adsorption process for adsorbing the film forming material on the surface of the wafer W, the purge process for substituting the atmosphere inside the chamber with the purge gas and the reaction process for carrying out the film forming reaction by supplying the thermal energy to the film forming material on the surface of the wafer W through the use of the energy transfer gas. Therefore, thin films can be sequentially deposited on the surface of the wafer W by repetitively performing the processes of the steps S12 to S18 inFIG. 4. The pressure increasing process of the step S15 and the pressure decreasing process of the step S17 are not prerequisite processes for the film formation. In other words, it is possible to perform the purge process of the step S14, the reaction process of the step S16 and the purge process of the step S18 while maintaining the inner pressure of thechamber1 at a constant level.
• After a desired film of a predetermined thickness is formed, the wafer W is unloaded from the loading/unloading port (not shown) by opening the gate valve (not shown) (step S19). In this way, the film forming process for a single wafer W is completed.
• Hereinafter, examples of major processes of the film forming method of the present invention will be described with reference toFIGS. 5 to 10.FIG. 5 provides a flowchart showing an example of a film forming reaction performed by introducing into the chamber1areactant gas in addition to an energy transfer gas during a reaction process.FIG. 6 offers a timing chart based on the flowchart ofFIG. 5. AlthoughFIG. 6 illustrates only a first to a third cycle for convenience, the number of cycles may be one or more than four depending on desired thin films (same inFIGS. 8,10 and14 to21). Since the details of each process are the same as those described above, the description thereof will be omitted.
• First of all, a source gas is adsorbed on a surface of a wafer W in a step S21. At this time, it is preferable that a temperature of the wafer W is controlled in advance as described above.
• Next, a first purge process is performed to purge a gaseous source gas in a step S22 (gaseous source gas purge process). Then, an inner pressure of thechamber1 is increased by controlling an exhaust conductance while introducing the purge gas in a pressure increasing process of a step S23. Herein, the purge process of the step S22 and the pressure increasing process of the step S23 are overlapped temporally. In a reaction process of a step S24, a film forming reaction is carried out by simultaneously supplying to the chamber a reactant gas in addition to an energy transfer gas.
• In a step25, the introduction of the energy transfer gas and the reactant gas is stopped and, also, the inner pressure of thechamber1 is decreased to a level before the pressure increasing process. Then, a second purge process is performed to purge reaction by-products and the energy transfer gas having the thermal energy (step S26).
• One cycle of the aforementioned steps S21 to S26 is repeated multiple times as necessary. Herein, the first purge process of the step S22 and the pressure increasing process of the step S23 can be performed simultaneously. Further, the pressure decreasing process of the step S25 and the second purge process of the step S26 can be performed simultaneously.
• FIG. 7 presents a flowchart describing an example of a film forming reaction performed by introducing into the chamber1areactant gas serving as an energy transfer gas. That is, the heated reactant gas can be used as the energy transfer gas.FIG. 8 represents a timing chart based on the flowchart ofFIG. 7. Since the details of each process are the same as those described above, the description thereof will be omitted.
• First of all, a source gas is adsorbed on a surface of a wafer W in a step S31. At this time, it is preferable that a temperature of the wafer W is controlled in advance as described above.
• Next, a first purge process is performed to purge a gaseous source gas in a step S32 (gaseous source gas purge process). Then, an inner pressure of thechamber1 is increased by controlling an exhaust conductance while introducing the purge gas in a pressure increasing process of a step S33. Herein, the purge process of the step S32 and the pressure increasing process of the step S33 are overlapped temporally. In a reaction process of a step S34, a film forming reaction is carried out by supplying to the chamber an energy transfer gas serving as a reactant gas. As for the energy transfer gas serving as the reactant gas, there can be employed, e.g., H₂, NH₃, N₂, N₂H₄, HCOOH, CH₃COOH, CH₃OH, H₂O (vapor), O₃, CO and the like.
• In a step35, the introduction of the energy transfer gas is stopped and, also, the inner pressure of thechamber1 is decreased to a level before the pressure increasing process. Then, a second purge process is performed to purge reaction by-products and the energy transfer gas having the thermal energy (step S36).
• One cycle of the aforementioned steps S31 to S36 is repeated multiple times as necessary. Herein, the first purge process of the step S32 and the pressure increasing process of the step S33 can be performed simultaneously. Further, the pressure decreasing process of the step S35 and the second purge process of the step S36 can be performed simultaneously.
• FIG. 9 is a flowchart showing an example of a film forming reaction performed by introducing only an energy transfer gas into thechamber1 during a reaction process. This is for a case where the film forming reaction is carried out by only supplying the thermal energy by the energy transfer gas without having to use the reactant gas.FIG. 10 illustrates a timing chart based on the flowchart ofFIG. 9. Since the details of each process are the same as those described above, the description thereof will be omitted.
• First of all, a source gas is adsorbed on a surface of a wafer W in a step S41. In such a case, it is preferable that a temperature of the wafer W is controlled in advance as described above.
• Next, a first purge process is performed to purge a gaseous source gas in a step S42 (gaseous source gas purge process). Then, an inner pressure of thechamber1 is increased by controlling an exhaust conductance while introducing the purge gas in a pressure increasing process of a step S43. Herein, the purge process of the step S42 and the pressure increasing process of the step S43 are overlapped temporally. In a reaction process of a step S44, a film forming reaction is carried out by supplying only the energy transfer gas into the chamber.
• In a step45, the introduction of the energy transfer gas is stopped and, also, the inner pressure of thechamber1 is decreased to a pressure level before the pressure increasing process. Then, a second purge process is performed to purge reaction by-products and the energy transfer gas having the thermal energy (step S46).
• One cycle of the aforementioned steps S41 to S46 is repeated multiple times as necessary. Herein, the first purge process of the step S42 and the pressure increasing process of the step S43 can be performed simultaneously. Further, the pressure decreasing process of the step S45 and the second purge process of the step S46 can be performed simultaneously.
• FIGS. 11A to 11J schematically illustrate a principle of a film forming process of this embodiment.FIG. 11A shows a wafer W having a temperature controlled to a level at which a source material can be easily adsorbed. Referring toFIG. 11B, a source material Si is adsorbed by contacting a source gas on a surface of the wafer W having the temperature controlled to a predetermined level. Next, as shown inFIG. 11C, the residual gaseous source material S₁is removed by performing a purge process with a purge gas P. After an inner pressure of thechamber1 is increased if necessary, a thermal energy E required for a reaction is supplied by injecting a reactant gas S₂and an energy transfer gas (not shown) heated to a high temperature toward the wafer W having the source material S₁adsorbed thereon, as illustrated inFIG. 11D. In this example, a chemical reaction takes place between the source material S₁and the reactant gas S₂, thereby forming a first layer of thin film D₁, as shown inFIG. 11E. Herein, the reactant gas S₂may not be used if not required.
• After the inner pressure of thechamber1 is decreased to a level before the pressure increasing process if necessary, the energy transfer gas having the thermal energy or the reaction by-products are removed by carrying out the purge process with the purge gas P, as illustrated inFIG. 11F. Therefore, in order to deposit a second layer of thin film, the source material S₁is adsorbed again on the wafer W (on the thin film D₁) (FIG. 11G) and, then, the purge process is performed (FIG. 11H). After increasing the inner pressure of thechamber1 if necessary, the reactant gas S₂and the energy transfer gas are injected (FIG. 11I). As a result, a chemical reaction takes place, forming a second layer of thin film D₂(FIG. 11J). Since the subsequent processes are the same as those for the first layer film forming process, the description thereof will be omitted. By repetitively performing the aforementioned processes, further layers of thin films are sequentially formed on top of the surface of the wafer W until a desired film thickness is achieved. AlthoughFIGS. 11A to 11J depict an example in which the film is formed by supplying the energy to a monomolecular adsorption layer adsorbed on the wafer W, a thin film can be deposited by supplying the energy to a multimolecular adsorption layer.
• FIG. 12 is a cross sectional view illustrating a schematic configuration of afilm forming apparatus101 in accordance with a second embodiment of the present invention. Thefilm forming apparatus101 is different from thefilm forming apparatus100 of the first embodiment in that agas exhaust port5 is formed on a bottom wall1aof achamber1 and connected with agas exhaust unit7 via agas exhaust line6 connected therewith, thegas exhaust unit7 having a high speed vacuum pump. It is preferable that thegas exhaust port5 and thegas inlet port17 are located at diametrically opposite locations with respect to the mounting table3. A conductancevariable valve6aserving as a pressure control unit is arranged on thegas exhaust line6 between thegas exhaust port5 and thegas exhaust unit7. By exhausting a gas inside thechamber1 with an operation of thegas exhaust unit7, an inner pressure of thechamber1 can be decreased to a predetermined vacuum level at a high speed via thegas exhaust line6 while controlling the pressure. Although thegas exhaust port5 is disposed as shown inFIG. 12, a flow of the source gas can be formed from thegas inlet port17 toward thegas exhaust port5 in a direction parallel to the surface of the wafer W mounted on the mounting table3, as indicated by white arrows ofFIG. 12. Consequently, the film forming source material can be effectively adsorbed on the surface of the wafer W. Since other configurations of thefilm forming apparatus101 in accordance with the second embodiment are the same as those of the film forming apparatus of the first embodiment, like reference numbers are given to like parts and the description thereof will be omitted.
• FIG. 13 provides a cross sectional view showing a schematic configuration of afilm forming apparatus102 in accordance with a third embodiment of the present invention. Unlike thefilm forming apparatus100 of the first embodiment or thefilm forming apparatus101 of the second embodiment, thefilm forming apparatus102 employs a structure in which a source gas, a purge gas, a reactant gas and an energy transfer gas are all supplied via a shower head.
• To be specific, ashower head60 is provided on aceiling wall1cof thechamber1 and includes anupper block body61, anintermediate block body62 and alower block body63. Alternately formed in thelower block body63 are gas injection openings64 and65 for discharging gases. A first and a secondgas inlet port66 and67 are formed on a top surface of theupper block body61. The firstgas inlet port66 is connected with an energy transfergas supply source23aand a reactantgas supply source23bvia abifurcated gas line72. The secondgas inlet port67 is connected with a film forming sourcegas supply source26 and a purgegas supply source27 via abifurcated gas line73. Moreover, the heated reactant gas can be used as the energy transfer gas. In such a case, the energy transfergas supply source23adoes not need to be provided in addition to the reactantgas supply source23b.
• A plurality ofgas channels68 are branched from the firstgas inlet port66 inside theupper block body61. Further,gas channels69 are formed in theintermediate block body62 and thegas channels68 communicate with thegas channels69. Furthermore, thegas channels69 communicate with the gas injection openings64 of thelower block body63.
• Moreover, a plurality ofgas channels70 are branched from the secondgas inlet port67 inside theupper block body61. In addition,gas channels71 are formed in theintermediate block body62 and thegas channels70 communicate with thegas channels71. Thegas channels71 communicate with the gas injection openings65 of thelower block body63.
• Provided around the gas injection openings64 areheaters74 serving as heating units for heating the energy transfer gas and the reactant gas inside theshower head60. Further, insulatingunits75 are provided around theheaters74 to insulate theheaters74, the insulatingunits75 being made of a material having a low thermal conductivity, e.g., heat resistant synthetic resin, quartz, ceramic or the like.
• Gas exhaust ports76aand76bare formed on a bottom wall1aof thechamber1, e.g., at diametrically opposite locations with respect to the mounting table3 and connected with agas exhaust unit7 having a high speed vacuum pump viagas exhaust lines77aand77bconnected therewith. By exhausting a gas inside thechamber1 with an operation of thegas exhaust unit7, an inner pressure of thechamber1 can be decreased to a predetermined vacuum level at a high speed via thegas exhaust lines77aand77b. Moreover, the pressure can be controlled to be increased or decreased by adjusting an exhaust conductance with the conductancevariable valves77cand77darranged on thegas exhaust lines77aand77bbetween thegas exhaust ports76aand76band thegas exhaust unit7 under the control of theprocess controller50. At this time, thegas exhaust unit7 and the conductancevariable valves77cand77dcooperatively serve as a pressure control unit.
• By connecting thegas line73 with theshower head60 as shown inFIG. 13, the source gas from the film forming sourcegas supply source26 is discharged through the gas injection openings65 of thelower block body63 facing the wafer W via the secondgas inlet port67 and thegas channels70 and71. Accordingly, the source gas can collide against the surface of the wafer W in a substantially vertical direction. Further, by exhausting the gas in thechamber1 through thegas exhaust ports76aand76bformed on the bottom wall1aof thechamber1, the source gas that has collided against the surface of the wafer W can flow toward thegas exhaust ports76aand76bin a direction substantially parallel to the surface of the wafer W mounted on the mounting table3. Consequently, the film forming material can be effectively adsorbed on the surface of the wafer W.
• By connecting thegas line72 with theshower head60, the energy transfer gas from the energy transfergas supply source23aand the reactant gas from the reactantgas supply source23bare discharged, if necessary, through the gas injection openings64 of thelower block body63 facing the wafer W via the firstgas inlet port66 and thegas channels68 and69. Accordingly, the energy transfer gas and the reactant gas collide against the surface of the wafer W in a substantially vertical direction. As a result, the thermal energy can be effectively supplied to the surface of the wafer W where the reaction takes place.
• Since other configurations of thefilm forming apparatus102 of the third embodiment are the same as those of thefilm forming apparatus100 of the first embodiment, like reference numbers are given to like parts and, further, the description thereof will be omitted.
• Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to following examples.
Example 1
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C.
• A liquid source material of Ru(EtCp)₂was introduced into a vaporizer heated to 150° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. As for an oxidizing gas (reactant gas), O₂was used. Introduced into thechamber1 were Ru(EtCp)₂, Ar serving as a carrier and dilution gas; and O₂serving as a reactant gas and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 14 shows a timing chart of the film forming process in this example:
• Step 1;
• Ru(EtCp)₂of 0.1 g/min and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr),
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing,
• Step 3;
• Ar and O₂, each being heated to 500° C., were set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). Each of the flow rates of Ar and O₂was 500 mL/min (sccm)
• Step 4;
• A purge process was performed by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 ten times, a Ru film having a film thickness of 30 nm was formed.
Example 2
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C.
• A liquid source material of Ru(EtCp)₂was introduced into a vaporizer heated to 150° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. Introduced into thechamber1 were Ru(EtCp)₂, Ar serving as a carrier and dilution gas; and H₂serving as a reactant gas and Ar as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 15 shows a timing chart of the film forming process in this example:
• Step 1;
• Ru(EtCp)₂of 0.2 g/min and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr).
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing,
• Step 3;
• Ar and H₂, each being heated to 500° C., were set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). Each of the flow rates of Ar and H₂was 500 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 eight times, a Ru film having a film thickness of 27 nm was formed.
Example 3
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C.
• A liquid source material of Ru(EtCp)₂was introduced into a vaporizer heated to 150° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. Introduced into thechamber1 were Ru(EtCp)₂, Ar serving as a carrier and dilution gas; and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 16 shows a timing chart of the film forming process in this example:
• Step 1;
• Ru(EtCp)₂of 0.2 g/min and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr).
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing.
• Step 3;
• Ar heated to 500° C. was set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Ar was 1000 mL/min (sccm).
• Step 4;
• A purge process was performed by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 eight times a Ru film having a film thickness of 29 nm was formed.
Example 4
• A wafer W having a diameter of 300 mm is loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C.
• A liquid source material of Ru(EtCp)₂was introduced into a vaporizer heated to 150° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. Introduced into thechamber1 were Ru(EtCp)₂, Ar serving as a carrier gas and dilution gas; and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 5:
• Step 1;
• Ru(EtCp)₂of 0.5 g/min and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr),
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing,
• Step 3;
• Ar heated to 500° C. was set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Ar was 1000 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr),
• Step 5;
• Ru(EtCp)₂of 0.5 g/min and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting the inner pressure of the chamber at 666.6 Pa (5 Torr).
• By performing four times thesteps 1 to 5 as a nucleation process and six times thesteps 5, 2, 3 and 4 as a main deposition process, a Ru film having a film thickness of 32 nm was formed.
Example 5
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 10° C.
• A solid source material of Ru₃(CO)₁₂in a vessel having a temperature controlled to 50° C. was introduced into the vacuum film forming apparatus by using a bubbling method employing Ar as a carrier gas.
• Introduced into the chamber were Ru₃(CO)₁₂, Ar serving as a carrier and dilution gas; and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 17 shows a timing chart of the film forming process in this example:
• Step 1;
• Ru₃(CO)₁₂of 1 mL/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr).
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing,
• Step 3;
• Ar heated to 500° C. was set to flow for 10 seconds while setting the pressure inside the chamber at 1333 Pa (10 Torr). The flow rate of Ar was 1000 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 fifty times, a Ru film having a film thickness of 5 nm was formed.
Example 6
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C.
• A source material of Ta(Nt-Am) (NMe₂)₃(=TAIMATA) was introduced into a vaporizer heated to 120° C. via a line heated to 50° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. Introduced into thechamber1 were Ta(Nt-Am) (NMe₂)₃, Ar serving as a carrier and dilution gas; and NH₃serving as a reactant gas and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 18 shows a timing chart of the film forming process in this example:
• Step 1;
• Ta(Nt-Am) (NMe₂)₃of 0.2 g/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr)
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing.
• Step 3;
• NH₃and Ar, each being heated to 500° C., were set to flow for 10 seconds at while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rates of NH₃and Ar were 700 and 300 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 eight times, a TaN film having a film thickness of 54 nm was formed.
Example 7
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C. A source of Ta(Nt-Am) (NMe₂)₃was introduced into a vaporizer heated to 120° C. via a line heated to 50° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. Introduced into thechamber1 were Ta(Nt-Am) (NMe₂)₃, Ar serving as a carrier and dilution gas; and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 19 shows a timing chart of the film forming process in this example:
• Step 1;
• Ta(Nt-Am) (NMe₂)₃of 0.2 g/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr).
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing.
• Step 3;
• Ar heated to 500° C. was set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Ar was 1000 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 ten times, a TaN film having a film thickness of 25 nm was formed.
Example 8
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 100° C.
• A source material of Ta(Nt-Am) (NMe₂)₃was introduced into a vaporizer heated to 120° C. via a line heated to 50° C. and, then, the vaporized gas was introduced into the vacuum film forming apparatus by a carrier gas of Ar. Introduced into thechamber1 were Ta(Nt-Am)(NMe₂)₃, Ar serving as a carrier and dilution gas; and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4:
• Step 1;
• Ta(Nt-Am) (NMe₂)₃of 0.2 g/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm) set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr).
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing.
• Step 3;
• Ar heated to 500° C. was set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Ar was 1000 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 ten times, a TaN film having a film thickness of 25 nm was formed.
Example 9
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 10° C.
• A solid source material of W(CO)₆in a vessel having a temperature controlled to 50° C. was introduced into the vacuum film forming apparatus by using a bubbling method employing Ar as a carrier gas. Introduced into the chamber were W(CO)₆, Ar serving as a carrier and dilution gas; and Ar serving as an energy transfer gas heated to a high temperature for a film forming reaction.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 20 provides a timing chart of the film forming process in this example:
• Step 1;
• W(CO)₆of 5 mL/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr).
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing.
• Step 3;
• Ar heated to 500° C. was set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Ar was 1000 mL/min (sccm).
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 twenty times, a W film having a film thickness of 10 nm was formed.
Example 10
• A wafer W having a diameter of 300 mm was loaded via a transfer robot (not shown) into an aluminum vacuum film forming apparatus having a mounting table whose temperature is controllable as inFIG. 1 and then mounted on the mounting table having a temperature controlled to a preset level of 10° C.
• A solid source material of W(CO)₆in a vessel having a temperature controlled to 50° C. was introduced into the vacuum film forming apparatus by using a bubbling method employing Ar as a carrier gas. Introduced into the chamber were W(CO)₆, Ar serving as a carrier and dilution gas; and H₂serving as a reactant gas heated to a high temperature for a film forming reaction and Ar as an energy transfer gas.
• Next, a film forming process was carried out by performing followingsteps 1 to 4.FIG. 21 provides a timing chart of the film forming process in this example:
• Step 1;
• W (CO)₆of 5 mL/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm) were set to flow for 20 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr),
• Step 2;
• A purge process was performed by flowing a dilution gas of Ar of 500 mL/min (sccm) as a purge gas for 10 seconds while setting an inner pressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressure of the chamber was increased to 1333 Pa (10 Torr) while the purge gas was flowing,
• Step 3;
• H₂and Ar, each being heated to 500° C., were set to flow for 10 seconds while setting the inner pressure of the chamber at 1333 Pa (10 Torr). The flow rates of H₂and Ar were 800 and 200 mL/min (sccm), respectively.
• Step 4;
• A purge process was carried out by flowing a dilution gas of Ar of 1000 mL/min (sccm) as a purge gas for 10 seconds while setting the inner pressure of the chamber at 400 Pa (3 Torr).
• By repeating thesteps 1 to 4 twenty times, a W film having a film thickness of 10 nm was formed.
• The present invention may be variously modified without being limited to the aforementioned embodiments.
• For example, although theheaters15 for heating the energy transfer gas are provided around thegas injection openings11 of theshower head10 in thefilm forming apparatus100 ofFIG. 1, the heaters may be installed in thediffusion space14 of theshower head10. In such a case, there can be used acylindrical heater210 having a bar-shapedresistance212 installed in an elongatedcylindrical container211 made of an insulating material such as heat resistant synthetic resin, quartz, ceramic or the like, as shown inFIGS. 22 and 23. The bar-shapedresistance212 is connected with a heater power supply (not shown) vialead lines215, so that an inside of thecontainer211 can be rapidly heated by supplying power to theheater210. Further, agas inlet213 is provided at one place of an upper portion of thecontainer211. A plurality ofgas outlets214 communicating with thegas injection openings11 of theshower head10 are formed at a lower portion of thecontainer211. The energy transfer gas can be rapidly heated while passing through the inside of thecontainer211. Moreover, a number of thecylindrical heaters210 may be disposed side by side inside thediffusion space14 of theshower head10.
• Although the first to the third embodiments employ the fixed mounting table3, there may be used a mounting table3 horizontally rotatable by a rotating unit. In such a case, a more uniform thickness and quality of a thin film formed on the surface of the wafer W can be achieved during the adsorption process for adsorbing a film forming material on the surface of the wafer W and the reaction process for carrying out a film forming reaction on the surface of the wafer W.
• The present invention can be appropriately used for forming a desired film on a substrate such as a semiconductor wafer or the like during a manufacturing process of various semiconductor devices, for example.

Claims (19)

1. A film forming apparatus comprising:

a processing chamber, accommodating therein a substrate, for performing a film forming process;

a mounting table for mounting thereon the substrate in the processing chamber;

a source gas inlet for introducing a source gas into the processing chamber;

an energy transfer gas inlet, which includes a plurality of gas injection openings, for injecting an energy transfer gas through the gas injection openings toward a surface of the substrate mounted on the mounting table in the processing chamber;

a gas exhaust unit for vacuum exhausting an inside of the processing chamber and;

a heater unit for heating the energy transfer gas,

wherein the heater unit is disposed in the energy transfer gas inlet such that the energy transfer gas is heated by the heater unit before being injected from the gas injections openings into the inside of the processing chamber.

2. The film forming apparatus ofclaim 1, wherein the heater unit includes cylindrical ceramic members and resistances embedded in a coil shape in the ceramic member, each of the gas injection openings being surrounded by one of the cylindrical ceramic members.

3. The film forming apparatus ofclaim 2, wherein insulation members are provided around the cylindrical ceramic members to thermally insulate the heater unit.

4. The film forming apparatus ofclaim 3, wherein the insulation members are made of a material selected from the group consisting of heat resistant synthetic resin, quartz and ceramic.

5. The film forming apparatus ofclaim 1, wherein the energy transfer gas inlet includes a shower head disposed in an upper portion of the processing chamber and having the gas injection openings and a diffusion space disposed thereabove and the heater unit installed in the diffusion space.

6. The film forming apparatus ofclaim 1, wherein the heater unit includes cylindrical heaters, each of which has an elongated cylindrical container made of an insulation material and a bar-shaped resistance installed in the elongated cylindrical container.

7. The film forming apparatus ofclaim 6, wherein the cylindrical container is provided with a gas inlet for introducing the energy transfer gas there into a plurality of gas outlets communicating with the gas injection openings, and the energy transfer gas is heated while passing through an inside of the cylindrical container.

8. The film forming apparatus ofclaim 7, wherein the cylindrical heaters are disposed side by side.

9. The film forming apparatus ofclaim 1, wherein power is supplied from a heater power supply to the heater unit via a lead line.

10. The film forming apparatus ofclaim 6, wherein the bar-shape resistance is connected with a heater power supply via lead lines, thereby rapidly heating the energy transfer gas at an inside of the cylindrical container by supplying electrical power to the heater unit.

11. A film forming apparatus comprising:

a processing chamber, accommodating therein a substrate, for performing a film forming process;

a mounting table for mounting thereon the substrate in the processing chamber;

a source gas inlet for introducing a source gas into the processing chamber;

an energy transfer gas inlet, which includes a plurality of gas injection openings, for injecting an energy transfer gas through the gas injection openings toward a surface of the substrate mounted on the mounting table in the processing chamber;

a gas exhaust unit for vacuum exhausting an inside of the processing chamber;

a heater unit for heating the energy transfer gas; and

a power supply connected to the heater unit to supply an electric power thereto,

wherein the heater unit is disposed inside the energy transfer gas inlet so that the energy transfer gas is heated by being introduced into the energy transfer gas inlet.

12. The film forming apparatus ofclaim 11, wherein the heater unit includes cylindrical ceramic members and resistances embedded in a coil shape in the ceramic member, each of the gas injection openings being surrounded by one of the cylindrical ceramics members.

13. The films forming apparatus ofclaim 12, wherein insulation members are provided around the cylindrical ceramic members to thermally insulate the heater unit.

14. The film forming apparatus ofclaim 13, wherein the insulation members are made of a material selected from the group consisting of heat resistant synthetic resin, quartz and ceramic.

15. The film forming apparatus ofclaim 11, wherein the energy transfer gas inlet includes a shower head disposed in an upper portion of the processing chamber and having the gas injection openings and a diffusion space disposed thereabove and the heater unit installed in the diffusion space.

16. The film forming apparatus ofclaim 11, wherein the heater unit includes cylindrical heaters, each of which has an elongated cylindrical container made of an insulation material and a bas-shaped resistance installed in the elongated cylindrical container.

17. The film forming apparatus ofclaim 16, wherein the cylindrical container is provided with a gas inlet for introducing the energy transfer gas thereinto a plurality of gas outlets communicating with the gas injection openings, and the energy transfer gas is heated while passing through an inside of the cylindrical container.

18. The film forming apparatus ofclaim 17, wherein the cylindrical heaters are disposed side by side.

19. The film forming apparatus ofclaim 16, wherein the bar-shape resistance is connected with the power supply via lead lines, thereby rapidly heating the energy transfer gas at an inside of the cylindrical container by supplying electrical power to the heater unit.

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